Staged blowdown of adsorbent bed

Abstract

A pressure swing adsorption (PSA) system using two or more valves for controlling the flow of gases entering or exiting a bed of adsorbents is disclosed, where the two or more valves are opened sequentially (i.e., in at least two actions separated by a delay in time). The sequential opening of the valves may increase the degree to which adsorbed species are purged from the bed, and also facilitates more rapid execution of certain time steps of the PSA cycle, thus increasing adsorbent productivity The sequential opening of the valves may also allow for verification of valve operation by measuring either the absolute value, the slope (derivative) or the rate of change of derivative of the pressure, either in the adsorbent bed, in the downstream manifold, or in a volume of gas held in a buffer vessel.

What is claimed is: 
     
       1. A pressure swing adsorption system, comprising:
 a plurality of vessels having one or more layers of adsorbent material therein; 
 a feed gas channel connected to the plurality of vessels; 
 a product recovery channel connected to the plurality of vessels; 
 a purge gas channel connected to the plurality of vessels; 
 a waste gas channel connected to the plurality of vessel; and 
 an equalization channel connected to the plurality of vessels; 
 the product recovery channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; and 
 a control system configured to open the at least two valves sequentially. 
 
     
     
       2. The system of  claim 1 , further comprising at least one of the following:
 the purge gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the waste gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the equalization channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 wherein, when the respective manifolds are present, the control system is configured to:
 open the at least two valves in the manifold connecting the purge gas channel sequentially; 
 open the at least two valves in the manifold connecting the waste gas channel sequentially; and 
 open the at least two valves in the manifold connecting the equalization channel sequentially. 
 
 
     
     
       3. The system of  claim 2 , wherein each of the valves in the respective manifolds is an on/off valve. 
     
     
       4. The system of  claim 3 , wherein the on/off valves in each respective manifold has a flow orifice of a similar diameter. 
     
     
       5. The system of  claim 3 , wherein the on/off valves in each respective manifold has a flow orifice of different diameters. 
     
     
       6. The system of  claim 5 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the product recovery channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the product recovery channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the product recovery channel, and the pressure sensor in the buffer vessel during the sequential opening of the at least two valves in the manifold connecting the product recovery channel. 
 
     
     
       7. The system of  claim 6 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the purge gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the purge gas channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the purge gas channel, and the pressure sensor in the buffer vessel fluidly connected to the purge gas channel during the sequential opening of the at least two valves in the manifold connecting the purge gas channel. 
 
     
     
       8. The system of  claim 7 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the waste gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the waste gas channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the waste gas channel, and the pressure sensor in the buffer vessel fluidly connected to the waste gas channel during the sequential opening of the at least two valves in the manifold connecting the waste gas channel. 
 
     
     
       9. The system of  claim 8 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the equalization channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the equalization channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the equalization channel, and the pressure sensor in the buffer vessel fluidly connected to the equalization channel during the sequential opening of the at least two valves in the manifold connecting the equalization channel. 
 
     
     
       10. The system of  claim 9 , wherein one or more of the respective manifolds comprises at least three valves, and wherein the control system is configured to open the at least three valves sequentially. 
     
     
       11. A pressure swing adsorption system, comprising:
 a plurality of vessels having one or more layers of adsorbent material therein; 
 a feed gas channel connected to the plurality of vessels; 
 a product recovery channel connected to the plurality of vessels; 
 a purge gas channel connected to the plurality of vessels; 
 a waste gas channel connected to the plurality of vessel; and 
 an equalization channel connected to the plurality of vessels; 
 the purge gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; and 
 a control system configured to open the at least two valves sequentially. 
 
     
     
       12. The system of  claim 11 , further comprising at least one of the following:
 the product recovery channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the waste gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the equalization channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 wherein, when the respective manifolds are present, the control system is configured to:
 open the at least two valves in the manifold connecting the product recovery channel sequentially; 
 open the at least two valves in the manifold connecting the waste gas channel sequentially; and 
 open the at least two valves in the manifold connecting the equalization channel sequentially. 
 
 
     
     
       13. The system of  claim 12 , wherein each of the valves in the respective manifolds is an on/off valve. 
     
     
       14. The system of  claim 13 , wherein the on/off valves in each respective manifold has a flow orifice of a similar diameter. 
     
     
       15. The system of  claim 13 , wherein the on/off valves in each respective manifold has a flow orifice of different diameters. 
     
     
       16. The system of  claim 15 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the purge gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the purge gas channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the purge gas channel, and the pressure sensor in the buffer vessel during the sequential opening of the at least two valves in the manifold connecting the purge gas channel. 
 
     
     
       17. The system of  claim 16 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the product recovery channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the product recovery channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the product recovery channel, and the pressure sensor in the buffer vessel fluidly connected to the product recovery channel during the sequential opening of the at least two valves in the manifold connecting the product recovery channel. 
 
     
     
       18. The system of  claim 17 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the waste gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the waste gas channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the waste gas channel, and the pressure sensor in the buffer vessel fluidly connected to the waste gas channel during the sequential opening of the at least two valves in the manifold connecting the waste gas channel. 
 
     
     
       19. The system of  claim 18 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the equalization channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the equalization channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the equalization channel, and the pressure sensor in the buffer vessel fluidly connected to the equalization channel during the sequential opening of the at least two valves in the manifold connecting the equalization channel. 
 
     
     
       20. The system of  claim 19 , wherein one or more of the respective manifolds comprises at least three valves, and wherein the control system is configured to open the at least three valves sequentially. 
     
     
       21. A pressure swing adsorption system, comprising:
 a plurality of vessels having one or more layers of adsorbent material therein; 
 a feed gas channel connected to the plurality of vessels; 
 a product recovery channel connected to the plurality of vessels; 
 a purge gas channel connected to the plurality of vessels; 
 a waste gas channel connected to the plurality of vessel; and 
 an equalization channel connected to the plurality of vessels; 
 the waste gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; and 
 a control system configured to open the at least two valves sequentially. 
 
     
     
       22. The system of  claim 21 , further comprising at least one of the following:
 the product recovery channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the purge gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the equalization channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 wherein, when the respective manifolds are present, the control system is configured to:
 open the at least two valves in the manifold connecting the product recovery channel sequentially; 
 open the at least two valves in the manifold connecting the purge gas channel sequentially; 
 open the at least two valves in the manifold connecting the equalization channel sequentially. 
 
 
     
     
       23. The system of  claim 22 , wherein each of the valves in the respective manifolds is an on/off valve. 
     
     
       24. The system of  claim 23 , wherein the on/off valves in each respective manifold has a flow orifice of a similar diameter. 
     
     
       25. The system of  claim 23 , wherein the on/off valves in each respective manifold has a flow orifice of different diameters. 
     
     
       26. The system of  claim 25 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the waste gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the waste gas channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the waste gas channel, and the pressure sensor in the buffer vessel during the sequential opening of the at least two valves in the manifold connecting the waste gas channel. 
 
     
     
       27. The system of  claim 26 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the purge gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the purge gas channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the purge gas channel, and the pressure sensor in the buffer vessel fluidly connected to the purge gas channel during the sequential opening of the at least two valves in the manifold connecting the purge gas channel. 
 
     
     
       28. The system of  claim 27 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the product recovery channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the product recovery channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the product recovery channel, and the pressure sensor in the buffer vessel fluidly connected to the product recovery channel during the sequential opening of the at least two valves in the manifold connecting the product recovery channel. 
 
     
     
       29. The system of  claim 28 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the equalization channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the equalization channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the equalization channel, and the pressure sensor in the buffer vessel fluidly connected to the equalization channel during the sequential opening of the at least two valves in the manifold connecting the equalization channel. 
 
     
     
       30. The system of  claim 29 , wherein one or more of the respective manifolds comprises at least three valves, and wherein the control system is configured to open the at least three valves sequentially. 
     
     
       31. A pressure swing adsorption system, comprising:
 a plurality of vessels having one or more layers of adsorbent material therein; 
 a feed gas channel connected to the plurality of vessels; 
 a product recovery channel connected to the plurality of vessels; 
 a purge gas channel connected to the plurality of vessels; 
 a waste gas channel connected to the plurality of vessel; and 
 an equalization channel connected to the plurality of vessels; 
 the equalization channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; and 
 a control system configured to open the at least two valves sequentially. 
 
     
     
       32. The system of  claim 31 , further comprising at least one of the following:
 the product recovery channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the purge gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the waste gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 wherein, when the respective manifolds are present, the control system is configured to:
 open the at least two valves in the manifold connecting the product recovery channel sequentially; 
 open the at least two valves in the manifold connecting the purge gas channel sequentially; and 
 open the at least two valves in the manifold connecting the waste gas channel sequentially. 
 
 
     
     
       33. The system of  claim 32 , wherein each of the valves in the respective manifolds is an on/off valve. 
     
     
       34. The system of  claim 33 , wherein the on/off valves in each respective manifold has a flow orifice of a similar diameter. 
     
     
       35. The system of  claim 33 , wherein the on/off valves in each respective manifold has a flow orifice of different diameters. 
     
     
       36. The system of  claim 35 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the equalization channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the equalization channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the equalization channel, and the pressure sensor in the buffer vessel during the sequential opening of the at least two valves in the manifold connecting the equalization channel. 
 
     
     
       37. The system of  claim 36 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the purge gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the purge gas channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the purge gas channel, and the pressure sensor in the buffer vessel fluidly connected to the purge gas channel during the sequential opening of the at least two valves in the manifold connecting the purge gas channel. 
 
     
     
       38. The system of  claim 37 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the waste gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the waste gas channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the waste gas channel, and the pressure sensor in the buffer vessel fluidly connected to the waste gas channel during the sequential opening of the at least two valves in the manifold connecting the waste gas channel. 
 
     
     
       39. The system of  claim 38 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the product recovery channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the product recovery channel; 
 wherein the control system is configured to determine a valve failure based upon the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the product recovery channel, and the pressure sensor in the buffer vessel fluidly connected to the product recovery channel during the sequential opening of the at least two valves in the manifold connecting the product recovery channel. 
 
     
     
       40. The system of  claim 39 , wherein one or more of the respective manifolds comprises at least three valves, and wherein the control system is configured to open the at least three valves sequentially. 
     
     
       41. A pressure swing adsorption system, comprising:
 a plurality of vessels having one or more layers of adsorbent material therein; 
 a feed gas channel connected to the plurality of vessels; 
 a product recovery channel connected to the plurality of vessels; 
 a purge gas channel connected to the plurality of vessels; 
 a waste gas channel connected to the plurality of vessel; and 
 an equalization channel connected to the plurality of vessels; 
 the product recovery channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the purge gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the waste gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; 
 the equalization channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; and 
 a control system configured to:
 open the at least two valves in the manifold connecting the product recovery channel sequentially; 
 open the at least two valves in the manifold connecting the purge gas channel sequentially; 
 open the at least two valves in the manifold connecting the waste gas channel sequentially; and 
 open the at least two valves in the manifold connecting the equalization channel sequentially. 
 
 
     
     
       42. The system of  claim 41 , wherein each of the valves in the respective manifolds is an on/off valve. 
     
     
       43. The system of  claim 42 , wherein the on/off valves in each respective manifold has a flow orifice of a similar diameter. 
     
     
       44. The system of  claim 42 , wherein the on/off valves in each respective manifold has a flow orifice of different diameters. 
     
     
       45. The system of  claim 44 , further comprising at least one of:
 a pressure sensor for measuring a pressure in each of the plurality of vessels; 
 a pressure sensor for measuring a pressure in the product recovery channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the product recovery channel; 
 a pressure sensor for measuring a pressure in the purge gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the purge gas channel; 
 a pressure sensor for measuring a pressure in the waste gas channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the waste gas channel; 
 a pressure sensor for measuring a pressure in the equalization channel; and 
 a pressure sensor for measuring a pressure in a buffer vessel fluidly connected to the equalization channel; 
 wherein the control system is configured to determine a valve failure based upon at least one of:
 the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the product recovery channel, and the pressure sensor in the buffer vessel fluidly connected to the product recovery channel during the sequential opening of the at least two valves in the manifold connecting the product recovery channel; 
 the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the purge gas channel, and the pressure sensor in the buffer vessel fluidly connected to the purge gas channel during the sequential opening of the at least two valves in the manifold connecting the purge gas channel; 
 the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the waste gas channel, and the pressure sensor in the buffer vessel fluidly connected to the waste gas channel during the sequential opening of the at least two valves in the manifold connecting the waste gas channel; 
 the pressure measured by at least one of, when present, the pressure sensor in each of the plurality of vessels, the pressure sensor in the equalization channel, and the pressure sensor in the buffer vessel fluidly connected to the equalization channel during the sequential opening of the at least two valves in the manifold connecting the equalization channel. 
 
 
     
     
       46. The system of  claim 45 , wherein one or more of the respective manifolds comprises at least three valves, and wherein the control system is configured to open the at least three valves sequentially. 
     
     
       47. The system of  claim 45 , wherein the respective at least two valves in a parallel flow arrangement are sized so as to maintain a velocity in the respective vessels below that which would fluidize the adsorbent materials therein. 
     
     
       48. The system of  claim 47 , wherein the control system is configured to open the valves sequentially based upon a pressure, a pressure differential, a rate of pressure change, or a rate of change in the rate of pressure change. 
     
     
       49. The system of  claim 48 , further comprising: the feed gas channel being connected to each of the plurality of vessels via a manifold comprising at least two valves in a parallel flow arrangement; and a control system configured to open the at least two feed valves sequentially. 
     
     
       50. A method of operating a pressure swing adsorption system comprising a plurality of vessels, a feed gas channel connected to the plurality of vessels, a product recovery channel connected to the plurality of vessels, a purge gas channel connected to the plurality of vessels, and a waste gas channel connected to the plurality of vessels, the method comprising at least one of:
 sequentially opening two or more valves disposed in a parallel flow arrangement and connecting one of the plurality of vessels to the product recovery channel; 
 sequentially opening two or more valves disposed in a parallel flow arrangement and connecting one of the plurality of vessels to the waste gas channel; 
 sequentially opening two or more valves disposed in a parallel flow arrangement and connecting one of the plurality of vessels to the equalization channel; and 
 sequentially opening two or more valves disposed in a parallel flow arrangement and connecting one of the plurality of vessels to the purge gas channel. 
 
     
     
       51. The method of  claim 50 , further comprising opening a redundant valve disposed in a parallel flow arrangement in response to a valve failure.